[postgis-tickets] [PostGIS] #2657: [raster] Respect imprecise real valued nodata

[PostGIS]

#2657: [raster] Respect imprecise real valued nodata
--------------------+-------------------------------------------------------
 Reporter:  mlt     |       Owner:  dustymugs    
     Type:  defect  |      Status:  new          
 Priority:  medium  |   Milestone:  PostGIS 2.1.2
Component:  raster  |     Version:  2.1.x        
 Keywords:  nodata  |  
--------------------+-------------------------------------------------------
 PostGIS should handle well real valued, e.g., fractional NODATA values,
 e.g. with ST_DumpAsPolygons.
 I suspect rounding takes place somewhere in the code as the following
 query from my testing database


 {{{
 select (gv).val, ST_Centroid((gv).geom) geom, (gv).val = nd
 from (
   select ST_DumpAsPolygons(ST_Union(ST_Clip(rast, geom)), 1, True) gv,
 ST_BandNoDataValue(rast,1) nd
   from dem, depressions
   where ST_Intersects(rast, geom)
         and gid=1
   group by gid, nd
 ) foo
 --where (gv).val!=(select ST_BandNoDataValue(rast,1) from dem where rid=1)
 order by (gv).val
 limit 1
 }}}

 returns

 -999.900024414063;"01010000202369000000000000BA4E1641000000A0CC825241";t

 whereas I'd either expect False for direct comparison with NODATA due to
 imprecision/rounding, or different value in the first column if PostGIS
 properly eliminated NODATA from the output.

 I'm using

 "POSTGIS="2.1.1 r12113" GEOS="3.4.2-CAPI-1.8.2 r3924" PROJ="Rel. 4.8.0, 6
 March 2012" GDAL="GDAL 1.10.0, released 2013/04/24" LIBXML="2.7.8"
 LIBJSON="UNKNOWN" TOPOLOGY RASTER"

 on Windows 7 64 bit.

-- 
Ticket URL: <http://trac.osgeo.org/postgis/ticket/2657>
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